69 lines
2.3 KiB
Java
69 lines
2.3 KiB
Java
package org.kne.cloud.network.ipv6;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import org.kne.cloud.network.NetworkPacket;
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import org.kne.io.KNEChannels;
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public class ICMPv6TimeExceededPacket extends ICMPv6Packet {
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private static final int UNUSED_FIELD_LENGTH = 4; // 未使用字段长度
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// 代码值常量
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public static final int CODE_HOP_LIMIT_EXCEEDED = 0; // 跳数限制超时
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public static final int CODE_FRAGMENT_REASSEMBLY_EXCEEDED = 1; // 分片重组超时
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public ICMPv6TimeExceededPacket(int code) {
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super(TYPE_TIME_EXCEEDED, code);
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setUnused(0);
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}
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/**
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* 获取未使用字段（通常为0）
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*/
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public int getUnused() {
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return getHeader().getInt(4);
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}
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/**
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* 设置未使用字段（通常设为0）
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*/
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public void setUnused(int unused) {
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getHeader().putInt(4, unused);
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}
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/**
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* 创建跳数限制超时包
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*/
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public static ICMPv6TimeExceededPacket createHopLimitExceeded(IPv6Packet originalPacket) {
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ICMPv6TimeExceededPacket packet = new ICMPv6TimeExceededPacket(CODE_HOP_LIMIT_EXCEEDED);
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// 包含原始数据包的前缀（根据RFC，尽可能包含但不超出最小MTU）
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if (originalPacket == null) {
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throw new NullPointerException("originalPacket is null!");
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}
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// 这里简化处理，实际应该序列化原始包的前1280字节（IPv6最小MTU）
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ByteBuffer buffer = NetworkPacket.bufferAllocator.allocate(65536);
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buffer.clear();
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try {
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originalPacket.writeToChannel(KNEChannels.newWritableChannel(buffer));
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} catch (IOException e) {
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e.printStackTrace();
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}
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buffer.flip();
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buffer.limit(Math.min(1280, buffer.limit()));
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packet.getData().clear();
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packet.getData().put(buffer);
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packet.getData().flip();
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return packet;
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}
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@Override
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public String toString() {
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String codeStr = getCode() == CODE_HOP_LIMIT_EXCEEDED ?
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"Hop Limit Exceeded" : "Fragment Reassembly Time Exceeded";
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return String.format("ICMPv6 Time Exceeded [%s, OriginalPrefix:%d bytes]",
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codeStr, getDataLength());
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}
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} |